Self-alining tap-holder.



E. W. CLEVELAND.

SELF ALINING TAP HOLDER.

APPLICATION FILED APR. 14. 1915.

Patented Oct. 5, 1915.

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r`:EDGAR W. CLEVELAND, OF RICHMOND, INDIANA, ASSIGNOR TO NATIONAL AUTOMATIC Y TOOL COMPANY, OF RICHMOND, INDIANA, A CORPORATION F INDIANA.

SELF-ALINING TAP-HOLDER.

Specification of Letters Patent.

Patented 0015.5, 1915.

. Application filed April 14, 1915. Serial No. 21,219.

tion from that which it normally takes, asv

required in order for yit to conform to the hole which the tap is-to follow.

In carrying out my invention, I make the tap holder of two main members, one for receiving the tap and the other for attachment to the driving spindle, and I provide these two members with two pairs of interengaging surfaces, such two pairs of interengaging surfaces being at axially separated v y points and at least one surface of each pair being tapered, and I provide one of such members with a supplemental spring-pressed member on which is one of the two surfaces of one of such pairs of surfaces, so that by the action of the spring-pressed member the two pairs of surfaces by their reaction tend to'maintain the two members in axial alinement and by the yielding of such springpressed member the inter-engaging surfaces of either or both pairs may slip relatively to each other to permit lateral displacement between the two members of the tap shank at either or both of the pairs of interengaging surfaces. When the slipping occurs at but one of the pairs of interengaging surfaces, the tap is displaced angular-ly. The same is true when there is an unequal slipping at the two pairs of interengaging surfaces. However, when there is an equal slipping at the two pairs of interengaging surfaces the tap is displaced laterally tota parallel position. A driving connection is provided between the two members of the tap holder` which driving connection permits the slipping referred to.

The accompanying drawing illustrates my invention.

Figure 1 is a vertical sectional view substantially on the line 1-1 of Fig. 4, showing a self-alining tap shank embodying my invention with the parts in their normal position; Fig. 2 is a similar view showing the bers 10 and 11.

two main. members of the tap holder displaced angularly; Fig. 3 is a somewhat similar view but on the line 3 3 of Fig. 4, showing the two members of the tap shank displaced parallelly; and Fig. l is a section on the line ,4f-4 of Fig. 1.

' The tap holder comprises two main members l() and 11. The member 10 is provided at its lower end with a suitable aperture 12 for receiving the butt end of a tap 13. The upper part of the member 11- is suitably shaped, as by having a long external taper, for fitting into the hollow end of the driving spindle. The lower end 15 of the member 11 extends into an axial hole 16 in the upper end of the member 10, the hole 1G beiugsuliciently larger than the part 15 prosuch hole and of the member 10 and the tap 13. In the lower end of the part 15 is anv axial hole 18 which receives first a compres- Sion spring 19 and then a plunger 20, which the spring 19 tends to force downward out of the hole 18. The lower end 21.-of the plunger 2O is conical to correspond with the bottom 17 of the hole 1G. The two surfaces '17 and 21 form one pair of inter-engaging tapering surfaces. At about the level of the upper end of the member 10, the member 11 is provided with a frusto-conical surface 22, which tapers in the opposite direction from the surfaces 17 and 21. This surface 22 bears against the inner part of the surface of a split ring 23, which has a seat 24. In the internal wall of the upper end of the member 10, which has' an axial recess 25 at the upper end for furnishing such seat. This recess 25 is conveniently larger' than the hole 1G, so as to provide between them a shoulder 26 which cooperates with a shoulder 27 on the member 11 below the conical surface 22, for limiting in one direction the relative. axial movement between the mem- Such relative axial movement is limited in the other direction by the engagement of the surface 22 with the split ring 23, these two surfaces forming a second pair of interengaging tapering surfaces, for the surface of the ring 23 is tangent to the tapering surface 22 at their point of engagement, so that that part of the surface of the ring 23 which engages the surface 22 isy correspondingly tapered. Though in the arrangement shown but a line engagement is provided between the surface 22 and the surface of the ring 23, since it is convenient to make such ring 23 of round wire, this is not essential, and a greater engagement may be provided if desired. lndeed, the surfaces 17, 21, and 22 may all be other than conical, though I now prefer the conical shape.

1n order to `provide a driving engagement between the members 10 and 11, the' member 11 is provided with a cross pin 28 which projects laterally from such member C11 below the shoulder 27 and into two opposite longitudinal slots 29 provided in the upper end of the member 10. The slots 29 are sufciently wider than the pin 28 to permit the desired movement between the members 1Q and 11, hereinafter set forth. The cross pin' 28 maybe of any convenient shape, and either integral with the member 10 or detachably mounted in such member.

In operation, the spring 19 tends to force the surfaces 21 and 17 together' and also to force the surface 22 against the ring 23, and

` by reason of the opposite taper of the sur- :sol

face 22 and the surfaces 17 and 21 the surface 21 tends to slide on the surface 17 and the surface 22 on the ring 23 to bring the members 10 and 11 into axial alinement, as shown in Fig. 1; or in other words to cause the two pairs of interengaging surfaces to center themselves relatively. When the member 11 is now driven, the member 10 is likewise driven, through the pin 28 in the slots 29, and the tap 13 is driven with the member 10. 1f the hole which receives the tap 13 is in alinement with the tap, the parts 10 and 11 remain as described. However, if there is a slight angular displacement between the hole which receives the tap and the tap itself, the tap swings angularly to follow the, hole, and the spring 19 yields to permit sliding of either the surface 22 on the ring 23 .or the surface 21 on the surface 17, or both, to permit angular displacement between the members 10 and 11, the member 11 still continuing to drive the member 10 and the tap 13 by the driving connection furnished by the pin 28 and the slots 29.v If' the hole which receives the tap is parallel to the'tap but laterally displaced therefrom, the tap is automatically displaced laterally to enter the hole, and the spring 19 yields to permit correspondingYslidingwof both the surface 21 on the surface 17 and the surface 22 on the ring 23, so that the axes of shown in Fig.,2 and the bodily lateral shifting shown in Fig. 3, but the yielding of the spring 11 and the sliding of the surfaces 17 and 2l and of the surface 22 on the interior of the ring 23 permits the tap 13 to follow the hole and the member 10 to shift as required by the tap.

I claim as my invention:

1. A self-alining holder comprising the combination of twol members, one for receiving atap and the other for mounting in a driving spindle, said two members having two pairs of interengaging surfaces, such two pairs of interengaging surfaces being tapering and being axially displaced from each other sufficiently so that there is no overlapping between them axially, and one of said members being provided with a springpressed member which carries one of these tapering surfaces, and a driving connection between such two members permitting relative lateraldisplacement between'the two members.

2. i A self-aliningholder, comprising a tapcarrying member, a member for mounting in a driving spindle, one of said members having an axial. hole and the other projecting into said axial hole, a spring-pressed plunger on the inwardly projecting end of' the member which projects into the hole, said spring-pressed plunger engaging the bottom of such hole and such bottom and the end of such spring-pressed plunger being correspondingly tapered, so that by the '.action'of the spring they tend to center themselves relatively, a pair of interengaging surfaces on the two members at an axially removed point from the first pair of self-centering surfaces, said second pair of interengaging surfaces also being tapered so that the action ofsuch spring tends to center them relatively, and a driving connection between the two members ermitting shifting of the interengaging sur aces.

3. A vself-alining holder, comprising two members, one for receiving a tap and the other for mounting in a driving spindle,` a spring-pressed plunger carried by one of such members, two pairs of interengaging surfaces axially removed from each other a distance greater than their diameters, one surface of one pair being on the springpressed plunger, one surface of the other pair being on the member which carries the spring-pressed plunger, and the other two surfaces of the two pairs being on the other member, and said surfaces being tapered so that the action of the springpressed plunger tends to center each pair of surfaces, and a driving connection between the two members permitting relative lateral displacement between the two members.

4. 'A self-alining holder comprising two members, one for mounting in a driving spindle and the other for receiving a tap, one of said members being provided with a ige ' spring-pressed plunger, said two membersbeing provided with a pair of interengaging surfaces and the spring-pressed plunger and the other member from that which-is provided with the spring-pressed plunger being provided with a second pair of interengaging surfaces, the two pairs of interengaging surfaces being axially removed so that they do not overlap axially and being tapered so that the action of the spring-pressed plunger tends to center each pair of interengaging surfaces relatively, and a driving connection between the two members permitting relative lateral displacement between the two members. d v

5. A self-alining holder comprising the combination of a member for receiving a tap, a member for mounting in. a driving spindle, a plunger on one of said members, a spring tending to force said spindle in one direction relatively to the member upon which it is mounted', said two' members being provided with one pair of interengaging surfaces and said plunger and the other member from that which carries the plunger being provided with another pair of interengaging surfaces, the two pairs of interengaging surfaces being axially removed so that they do not overlap axially, the two surfaces of each pair of interengaging vsurfaces being relatively self-centering under the action of said spring, and a driving connection between the two members permitting relative lateral displacement between the two members.

6. A self-alining holder, comprising thev ment between them.

7. A self-alining holder, comprising the ,combination of two members, one for receiving a tap and the other for mounting in a driving spindle, said two members having two pairs of interengaging surfaces, such two pairs of mterengagmg surfaces being tapering and being suiiiciently displaced from each other so that the normals to the surfaces of either pair within the area of their engagement pass outside the area of engagement of the surfaces of the other pairon the same side of the axis of such surfaces, and ,one of said members being provided with a spring-pressed member which carries one-of these tapering surfaces, and a driving connection between such two members permitting relative lateral displacement between-the two members. .In witness whereof, I have hereunto se i my hand at Richmond, Indiana, this eighth day of April, A. D' one thousand nine hundred and fifteen.

. EDGAR w. CLEVELAND. 

